EFFECT OF MOISTURE CONTENT ON MECHANICAL PROPERTIES OF RICE KERNELS UNDER QUASI-STATIC COMPRESSIVE LOADING.

Quasi-static compressive tests to determine the static mechanical properties of individual rice kernels were carried out on specimens tested uniaxially along the longitudinal axis. Apparent elastic modulus, failure stress, failure strain and energy density at failure were determined at five or six different moisture content levels ranging from 5% to 30% on dry basis (db). Compression speeds of 5 mm min** minus **1 and 10 mm min** minus **1 were used. Statistical analysis of the test results showed that moisture content had profound influence on the properties examined, especially in the range of 12% db to 18% db where quite drastic changes occur. An explanation in terms of bound water and free water in the kernel is given.